Plastic barrel, optical lens assembly, imaging apparatus and electronic device

ABSTRACT

A plastic barrel includes an object-end portion, an image-end portion and a tube portion. The object-end portion includes an object-end surface and an object-end hole, wherein the object-end surface includes a plurality of annular grooves, which are disposed coaxially to a central axis, and each of the annular grooves includes a stepped surface. The image-end portion includes an image-end opening. The tube portion connects the object-end portion and the image-end portion.

RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number104210894, filed Jul. 6, 2015, which is herein incorporated byreference.

BACKGROUND

Technical Field

The present disclosure relates to a plastic barrel and an optical lensassembly. More particularly, the present disclosure relates to a plasticbarrel and an optical lens assembly which are applicable to portableelectronic devices.

Description of Related Art

Due to the popularity of personal electronic products and mobilecommunication products having camera functionalities, such as smartphones and tablet personal computers, the demand for compact opticallens assemblies has been increasing and the requirements for highresolution and image quality of present compact optical lens assembliesincrease significantly.

A plastic barrel is generally used to carry an optical lens assembly andprovide an optical space between any two lens elements thereof. Asurface property of the plastic barrel relates to an effect ofsuppressing unexpected lights. Accordingly, an image quality of theoptical lens assembly is influenced by the surface property of theplastic barrel.

A conventional plastic barrel is typically formed by an injectionmolding method and has a smooth and bright surface, which is featuredwith high reflectivity. As a result, the conventional plastic barrelcannot suppress unexpected lights.

Another conventional plastic barrel is provided for suppressingunexpected lights. The conventional plastic barrel is atomized with asurface treatment, so that a reflectivity thereof is reduced. However,the effect of suppressing unexpected lights is still limited. Therefore,the conventional plastic barrel cannot satisfy the requirements ofhigh-end optical systems with camera functionalities.

Given the above, how to improve the surface property of the plasticbarrel for enhancing the image quality of compact optical lensassemblies has become one of the important subjects.

SUMMARY

According to one aspect of the present disclosure, a plastic barrelincludes an object-end portion, an image-end portion and a tube portion.The object-end portion includes an object-end surface and an object-endhole, wherein the object-end surface includes a plurality of annulargrooves, which are disposed coaxially to a central axis, and each of theannular grooves includes a stepped surface. The image-end portionincludes an image-end opening. The tube portion connects the object-endportion and the image-end portion.

According to another aspect of the present disclosure, an optical lensassembly includes a plastic barrel and a lens module. The plastic barrelincludes an object-end portion, an image-end portion and a tube portion.The object-end portion includes an object-end surface and an object-endhole, wherein the object-end surface includes a plurality of steppedsurfaces disposed coaxially to a central axis. The image-end portionincludes an image-end opening. The tube portion connects the object-endportion and the image-end portion. The lens module is disposed in theplastic barrel and includes a plurality of lens elements. When adiameter of the object-end hole is φo, the following condition issatisfied:

φo<4.5 mm.

According to another aspect of the present disclosure, an imagingapparatus includes the optical lens assembly according to the foregoingaspect.

According to another aspect of the present disclosure, an electronicdevice includes the imaging apparatus according to the foregoing aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a plastic barrel according to the 1stembodiment of the present disclosure;

FIG. 1B is an enlarged view of part 1B in FIG. 1A;

FIG. 2A is a schematic view of a plastic barrel according to the 2ndembodiment of the present disclosure;

FIG. 2B is an enlarged view of part 2B in FIG. 2A;

FIG. 3A is a schematic view of a plastic barrel according to the 3rdembodiment of the present disclosure;

FIG. 3B is an enlarged view of part 3B in FIG. 3A;

FIG. 4A is a schematic view of a plastic barrel according to the 4thembodiment of the present disclosure;

FIG. 4B is an enlarged view of part 4B in FIG. 4A;

FIG. 5 shows an optical lens module according to the 5th embodiment ofthe present disclosure;

FIG. 6 shows an electronic device according to the 6th embodiment of thepresent disclosure;

FIG. 7 shows an electronic device according to the 7th embodiment of thepresent disclosure; and

FIG. 8 shows an electronic device according to the 8th embodiment of thepresent disclosure.

DETAILED DESCRIPTION 1st Embodiment

FIG. 1A is a schematic view of a plastic barrel 100 according to the 1stembodiment of the present disclosure. The plastic barrel 100 includes anobject-end portion 110, an image-end portion 120 and a tube portion 130.

The object-end portion 110 includes an object-end surface 111 and anobject-end hole 116, wherein the object-end hole 116 is surrounded bythe object-end surface 111. The object-end surface 111 includes aplurality of annular grooves 140, which are disposed coaxially to acentral axis, and each of the annular grooves 140 includes a steppedsurface (its reference numeral is omitted). Therefore, it is favorablefor reducing the reflected lights effectively so as to improve the imagequality.

The image-end portion 120 includes an image-end opening 121. Theimage-end opening 121 and the object-end hole 116 are disposed on animage side and an object side along the central axis of the plasticbarrel 100, respectively.

The tube portion 130 has a tubular shape along the central axis andconnects the object-end portion 110 and the image-end portion 120.

In details, the annular grooves 140 and the plastic barrel 100 can beformed integrally. Therefore, it is favorable for maintaining theconveniences of manufacturing of the plastic barrel 100.

The object-end surface 111 can further include an outer object-endsurface 112 and an inner object-end surface 114. The inner object-endsurface 114 is disposed opposite to the outer object-end surface 112,wherein the outer object-end surface 112 is closer to an object (notshown) than the inner object-end surface 114, and the annular grooves140 are disposed on the outer object-end surface 112. Therefore, it isfavorable for reducing the reflected lights effectively so as to improvethe image quality. Furthermore, the annular grooves can be continuouslydisposed or can have an interval between every two of the annulargrooves adjacent to each other. According to the 1st embodiment of thepresent disclosure, the annular grooves 140 are continuously disposed.

The outer object-end surface 112 can include an outer flat surface 113orthogonal to the central axis. Therefore, it is favorable for obtaininga structural reference of the annular grooves 140 so as to ensure thestability in dimension.

Furthermore, the tube portion 130 can include a screw thread 131,wherein the screw thread 131 is disposed on the outer surface of thetube portion 130. Therefore, it is favorable for maintaining thestability of assembling of the plastic barrel 100 and an optical lensassembly or an actuator.

According to the 1st embodiment of the present disclosure, when adiameter of the object-end hole 116 is φo, the following condition canbe satisfied: φo<4.5 mm. Therefore, it is favorable for the plasticbarrel 100 applied to the optical lens assembly with compact size.

According to the 1st embodiment of the present disclosure, when adistance parallel to the central axis between the object-end hole 116and the image-end opening 121 is TL, and the diameter of the object-endhole 116 is φo, the following condition can be satisfied:1.35<TL/φo<2.75. Therefore, it is favorable for the plastic barrel 100applied to the optical lens assembly with high-end properties.Preferably, the following condition is satisfied: 1.50<TL/φo<2.25.

According to the 1st embodiment of the present disclosure, when a numberof the annular grooves 140 is M, the following condition can besatisfied: M 8. Therefore, it is favorable for maintaining the effectsof reducing the reflected lights of the annular grooves 140.

FIG. 1B is an enlarged view of part 1B in FIG. 1A. According to the 1stembodiment of the present disclosure, the stepped surface of each of theannular grooves 140 can include a plurality of orthogonal steppedsurfaces 141 and a plurality of parallel stepped surfaces 142, whereinthe orthogonal stepped surfaces 141 are orthogonal to the central axisand the parallel stepped surfaces 142 are parallel to the central axis.One of the orthogonal stepped surfaces of each of the annular grooves140 is a groove bottom 143, and each of other two of the orthogonalstepped surfaces of each of the annular grooves 140 is a groove end 145.A distance parallel to the central axis between the groove bottom 143and the outer flat surface 113 is greatest among distances parallel tothe central axis between the orthogonal stepped surfaces 141 and theouter flat surface 113. The two groove ends 145 are disposed on theother two of the orthogonal stepped surfaces located on two ends of theannular grooves 140 respectively, and a distance parallel to the centralaxis between each of the two groove ends 145 and the outer flat surface113 is smaller than distances parallel to the central axis between theorthogonal stepped surfaces 141 adjacent to thereof and the outer flatsurface 113. That is, the distance parallel to the central axis betweeneach of the two groove ends 145 and the outer flat surface 113 issmaller than distances parallel to the central axis between theorthogonal stepped surfaces 141 adjacent to thereof and the outer flatsurface 113, so each of the two groove ends 145 is the boundary of twoannular grooves 140 adjacent to each other. In the 1st embodiment, theannular grooves 140 are continuously disposed. Hence, the boundarybetween two annular grooves 140, which are adjacent to each other, isthe same one of the groove ends 145 (the same one of the orthogonalstepped surfaces), wherein the foregoing one of the groove ends 145 isone of the orthogonal stepped surfaces included in two annular grooves140 which are adjacent to each other. When a number of the orthogonalstepped surfaces 141 of at least one of the annular grooves 140 is N,the following condition can be satisfied: 4≦N≦8. Therefore, it isfavorable for maintaining the effects of reducing the reflected lightsof the stepped surfaces of the annular grooves 140.

Furthermore, when a sum of the orthogonal stepped surfaces 141 of eachof the annular grooves 140 is ΣN, the following condition can besatisfied: 7≦ΣN. Therefore, it is favorable for maintaining the effectsof reducing the reflected lights of the stepped surfaces of the annulargrooves 140.

According to the 1st embodiment of the present disclosure, when thedistance parallel to the central axis between one of the two groove ends145 and the outer flat surface 113 is smaller than the distance parallelto the central axis between the other one of the two groove ends 145 andthe outer flat surface 113, and a distance parallel to the central axisbetween the one of the two groove ends 145 and the groove bottom 143 ish, the following condition can be satisfied: 0.02 mm<h<0.25 mm.Therefore, it is favorable for obtaining a significant surface structureof the annular grooves 140 so as to reduce the reflected lightseffectively and improve the image quality.

The data of the aforementioned parameters of the plastic barrel 100according to the 1st embodiment of the present disclosure are listed inthe following Table 1. According to the 1st embodiment, a number of themain annular grooves 140 which respectively have 4 to 8 orthogonalstepped surfaces 141 is M, the number of the orthogonal stepped surfaces141 of the annular grooves 140 aforementioned is N, and the parameter his listed in Table 1. The sum of the orthogonal stepped surfaces 141 ofeach of the annular grooves 140 of the plastic barrel 100 is ΣN. Thedata are also shown as FIG. 1A and FIG. 1B.

TABLE 1 1st Embodiment φo (mm) 2.06 N 5 TL (mm) 3.60 h (mm) 0.15 TL/φo1.75 ΣN 9 M 2

2nd Embodiment

FIG. 2A is a schematic view of a plastic barrel 200 according to the 2ndembodiment of the present disclosure. The plastic barrel 200 includes anobject-end portion 210, an image-end portion 220 and a tube portion 230.

The object-end portion 210 includes an object-end surface 211 and anobject-end hole 216, wherein the object-end hole 216 is surrounded bythe object-end surface 211. The object-end surface 211 includes aplurality of annular grooves 240, which are disposed coaxially to acentral axis, and each of the annular grooves 240 includes a steppedsurface (its reference numeral is omitted).

The object-end surface 211 further includes an outer object-end surface212 and an inner object-end surface 214. The inner object-end surface214 is disposed opposite to the outer object-end surface 212, whereinthe outer object-end surface 212 is closer to an object (not shown) thanthe inner object-end surface 214, the outer object-end surface 212includes an outer flat surface 213 orthogonal to the central axis, andthe annular grooves 240 are disposed on the outer object-end surface212. Furthermore, the annular grooves 240 and the plastic barrel 200 areformed integrally.

The image-end portion 220 includes an image-end opening 221. Theimage-end opening 221 and the object-end hole 216 are disposed on animage side and an object side along the central axis of the plasticbarrel 200, respectively. The tube portion 230 has a tubular shape alongthe central axis and connects the object-end portion 210 and theimage-end portion 220.

FIG. 2B is an enlarged view of part 2B in FIG. 2A. According to the 2ndembodiment of the present disclosure, the stepped surface of each of theannular grooves 240 includes a plurality of orthogonal stepped surfaces241 and a plurality of parallel stepped surfaces 242, wherein theorthogonal stepped surfaces 241 are orthogonal to the central axis andthe parallel stepped surfaces 242 are parallel to the central axis. Oneof the orthogonal stepped surfaces of each of the annular grooves 240 isa groove bottom 243, and each of other two of the orthogonal steppedsurfaces of each of the annular grooves 240 is a groove end 245. Adistance parallel to the central axis between the groove bottom 243 andthe outer flat surface 213 is greatest among distances parallel to thecentral axis between the orthogonal stepped surfaces 241 and the outerflat surface 213. The two groove ends 245 are disposed on the other twoof the orthogonal stepped surfaces located on two ends of the annulargrooves 240 respectively.

The data of the parameters φ, TL, TL/φo, M, N, h and ΣN of the plasticbarrel 200 according to the 2nd embodiment of the present disclosure arelisted in the following Table 2. The definitions of these parametersshown in Table 2 are the same as those stated in the 1st embodiment withcorresponding values for the 2nd embodiment. According to the 2ndembodiment, a number of the main annular grooves 240 which respectivelyhave 4 to 8 orthogonal stepped surfaces 241 is M, the number of theorthogonal stepped surfaces 241 of the annular grooves 240aforementioned is N, and the parameter h is listed in Table 2. The sumof the orthogonal stepped surfaces 241 of each of the annular grooves240 of the plastic barrel 200 is ΣN. The data are also shown as FIG. 2Aand FIG. 2B.

TABLE 2 2nd Embodiment φo (mm) 1.95 N 4 TL (mm) 3.60 h (mm) 0.15 TL/φo1.85 ΣN 10 M 3

3rd Embodiment

FIG. 3A is a schematic view of a plastic barrel 300 according to the 3rdembodiment of the present disclosure. The plastic barrel 300 includes anobject-end portion 310, an image-end portion 320 and a tube portion 330.

The object-end portion 310 includes an object-end surface 311 and anobject-end hole 316, wherein the object-end hole 316 is surrounded bythe object-end surface 311. The object-end surface 311 includes aplurality of annular grooves 340, which are disposed coaxially to acentral axis, and each of the annular grooves 340 includes a steppedsurface (its reference numeral is omitted).

The object-end surface 311 further includes an outer object-end surface312 and an inner object-end surface 314. The inner object-end surface314 is disposed opposite to the outer object-end surface 312, whereinthe outer object-end surface 312 is closer to an object (not shown) thanthe inner object-end surface 314, and the annular grooves 340 aredisposed on the inner object-end surface 314. Therefore, it is favorablefor reducing the reflected lights effectively so as to improve the imagequality. Furthermore, the annular grooves can be continuously disposedor can have an interval between every two of the annular groovesadjacent to each other. According to the 3rd embodiment of the presentdisclosure, the annular grooves 340 are continuously disposed.

The annular grooves 340 and the plastic barrel 300 are formedintegrally. The outer object-end surface 312 includes an outer flatsurface 313 orthogonal to the central axis.

Moreover, the outer object-end surface 312 can further include an innerflat surface 315 orthogonal to the central axis. Therefore, it isfavorable for obtaining a structural reference of the annular grooves340 so as to ensure the stability in dimension.

The image-end portion 320 includes an image-end opening 321. Theimage-end opening 321 and the object-end hole 316 are disposed on animage side and an object side along the central axis of the plasticbarrel 300, respectively. The tube portion 330 includes a screw thread331, wherein the screw thread 331 is disposed on the outer surface ofthe tube portion 330.

FIG. 3B is an enlarged view of part 3B in FIG. 3A. According to the 3rdembodiment of the present disclosure, the stepped surface of each of theannular grooves 340 can include a plurality of orthogonal steppedsurfaces 341 and a plurality of parallel stepped surfaces 342, whereinthe orthogonal stepped surfaces 341 are orthogonal to the central axisand the parallel stepped surfaces 342 are parallel to the central axis.One of the orthogonal stepped surfaces of each of the annular grooves340 is a groove bottom 343, and each of other two of the orthogonalstepped surfaces of each of the annular grooves 340 is a groove end 345.A distance parallel to the central axis between the groove bottom 343and the inner flat surface 315 is greatest among distances parallel tothe central axis between the orthogonal stepped surfaces 341 and theinner flat surface 315. The two groove ends 345 are disposed on theother two of the orthogonal stepped surfaces located on two ends of theannular grooves 340 respectively, and a distance parallel to the centralaxis between each of the two groove ends 345 and the inner flat surface315 is smaller than distances parallel to the central axis between theorthogonal stepped surfaces 341 adjacent to thereof and the inner flatsurface 315. That is, the distance parallel to the central axis betweeneach of the two groove ends 345 and the inner flat surface 315 issmaller than distances parallel to the central axis between theorthogonal stepped surfaces 341 adjacent to thereof and the inner flatsurface 315, so each of the two groove ends 345 is the boundary of twoannular grooves 340 adjacent to each other. In the 3rd embodiment, theannular grooves 340 are continuously disposed. Hence, the boundarybetween two annular grooves 340, which are adjacent to each other, isthe same one of the groove ends 345 (the same one of the orthogonalstepped surfaces), wherein the foregoing one of the groove ends 345 isone of the orthogonal stepped surfaces included in two annular grooves340 which are adjacent to each other.

According to the 3rd embodiment of the present disclosure, when thedistance parallel to the central axis between one of the two groove ends345 and the inner flat surface 315 is smaller than the distance parallelto the central axis between the other one of the two groove ends 345 andthe inner flat surface 315, and a distance parallel to the central axisbetween the one of the two groove ends 345 and the groove bottom 343 ish, the following condition can be satisfied: 0.02 mm<h<0.25 mm.Therefore, it is favorable for obtaining a significant surface structureof the annular grooves 340 so as to reduce the reflected lightseffectively and improve the image quality.

The data of the parameters φ, TL, TL/φo, M, N, h and ΣN of the plasticbarrel 300 according to the 3rd embodiment of the present disclosure arelisted in the following Table 3. The definition of parameter h is asabove, and the definitions of other parameters shown in Table 3 are thesame as those stated in the 1st embodiment with corresponding values forthe 3rd embodiment. According to the 3rd embodiment, a number of themain annular grooves 340 which respectively have 4 to 8 orthogonalstepped surfaces 341 is M, the number of the orthogonal stepped surfaces341 of the annular grooves 340 aforementioned is N, and the parameter his listed in Table 3. The sum of the orthogonal stepped surfaces 341 ofeach of the annular grooves 340 of the plastic barrel 300 is ΣN. Thedata are also shown as FIG. 3A and FIG. 3B.

TABLE 3 3rd Embodiment φo (mm) 1.19 N 5 TL (mm) 2.18 h (mm) 0.10 TL/φo1.83 ΣN 9 M 2

4th Embodiment

FIG. 4A is a schematic view of a plastic barrel 400 according to the 4thembodiment of the present disclosure. The plastic barrel 400 includes anobject-end portion 410, an image-end portion 420 and a tube portion 430.

The object-end portion 410 includes an object-end surface 411 and anobject-end hole 416, wherein the object-end hole 416 is surrounded bythe object-end surface 411. The object-end surface 411 includes aplurality of annular grooves 440, which are disposed coaxially to acentral axis, and each of the annular grooves 440 includes a steppedsurface (its reference numeral is omitted).

The object-end surface 411 further includes an outer object-end surface412 and an inner object-end surface 414. The inner object-end surface414 is disposed opposite to the outer object-end surface 412, whereinthe outer object-end surface 412 is closer to an object (not shown) thanthe inner object-end surface 414, the outer object-end surface 412includes an outer flat surface 413 orthogonal to the central axis, andthe annular grooves 440 are disposed on the outer object-end surface412. Furthermore, the annular grooves 440 and the plastic barrel 400 areformed integrally.

The image-end portion 420 includes an image-end opening 421. Theimage-end opening 421 and the object-end hole 416 are disposed on animage side and an object side along the central axis of the plasticbarrel 400, respectively. The tube portion 430 has a tubular shape alongthe central axis and connects the object-end portion 410 and theimage-end portion 420. Moreover, the tube portion 430 includes a screwthread 431, wherein the screw thread 431 is disposed on the outersurface of the tube portion 430.

FIG. 4B is an enlarged view of part 4B in FIG. 4A. According to the 4thembodiment of the present disclosure, the stepped surface of each of theannular grooves 440 includes a plurality of orthogonal stepped surfaces441 and a plurality of parallel stepped surfaces 442, wherein theorthogonal stepped surfaces 441 are orthogonal to the central axis andthe parallel stepped surfaces 442 are parallel to the central axis. Oneof the orthogonal stepped surfaces of each of the annular grooves 440 isa groove bottom 443, and each of other two of the orthogonal steppedsurfaces of each of the annular grooves 440 is a groove end 445. Adistance parallel to the central axis between the groove bottom 443 andthe outer flat surface 413 is greatest among distances parallel to thecentral axis between the orthogonal stepped surfaces 441 and the outerflat surface 413. The two groove ends 445 are disposed on the other twoof the orthogonal stepped surfaces located on two ends of the annulargrooves 440 respectively.

The data of the parameters φ, TL, TL/φo, M, N, h and ΣN of the plasticbarrel 400 according to the 4th embodiment of the present disclosure arelisted in the following Table 4. The definitions of these parametersshown in Table 4 are the same as those stated in the 1st embodiment withcorresponding values for the 4th embodiment. According to the 4thembodiment, a number of the main annular grooves 440 which respectivelyhave 4 to 8 orthogonal stepped surfaces 441 is M, the number of theorthogonal stepped surfaces 441 of the annular grooves 440aforementioned is N, the number of the annular grooves 440 (M) whichrespectively have 5 orthogonal stepped surfaces 441 (N) is 2, the numberof the annular grooves 440 (M) which respectively have 4 orthogonalstepped surfaces 441 (N) is 1, and the parameter h is listed in Table 4.The sum of the orthogonal stepped surfaces 441 of each of the annulargrooves 440 of the plastic barrel 400 is ΣN. The data are also shown asFIG. 4A and FIG. 4B.

TABLE 4 4th Embodiment φo (mm) 1.19 N 5 4 TL (mm) 2.10 h (mm) 0.10 TL/φo1.76 ΣN 12 M 3

5th Embodiment

FIG. 5 shows an optical lens module 1000 according to the 5th embodimentof the present disclosure. The optical lens assembly 1000 includes theplastic barrel 400 and a lens module 1100.

The lens module 1100 is disposed in the plastic barrel 400 and includesa plurality of lens elements (1110-1140).

In FIG. 4A and FIG. 4B, the plastic barrel 400 includes the object-endportion 410, the image-end portion 420 and the tube portion 430. Theobject-end portion 410 includes the object-end surface 411 and theobject-end hole 416, wherein the object-end hole 416 is surrounded bythe object-end surface 411, and the object-end surface 411 includes aplurality of stepped surface (its reference numeral is omitted) disposedcoaxially to the central axis. Therefore, it is favorable for reducingthe reflected lights effectively so as to improve the image quality.

The image-end portion 420 includes the image-end opening 421. Theimage-end opening 421 and the object-end hole 416 are disposed on theimage side and the object side along the central axis of plastic barrel400, respectively. The tube portion 430 has the tubular shape along thecentral axis and connects the object-end portion 410 and the image-endportion 420. The other details of the plastic barrel 400 have beendescribed in the foregoing paragraphs and will not be repeated herein.

According to the 5th embodiment of the present disclosure, when thediameter of the object-end hole 416 of the plastic barrel 400 is To, thefollowing condition is satisfied: φo<4.5 mm. Therefore, it is favorablefor the plastic barrel 400 to be applied to the optical lens assembly1000 with compact size.

In details, the lens module 1100 includes, in order from the object-endportion 410 of the plastic barrel 400 to the image-end portion 420thereof, the first lens element 1110, the second lens element 1120, thethird lens element 1130 and the fourth lens element 1140, wherein thelens elements 1110-1140 are respectively abutted with a plurality ofoptical elements (its reference numeral is omitted) so as to be disposedin the plastic barrel 400.

Furthermore, the plastic barrel 400 can be formed by an injectionmolding method. Therefore, it is favorable for mass production.

The object-end hole 416 of the plastic barrel 400 can be an aperturestop of the optical lens assembly 1000. Therefore, it is favorable forreducing the complexity of mechanism design.

According to the 5th embodiment of the present disclosure, when thedistance parallel to the central axis between the object-end hole 416and the image-end opening 421 is TL, and the diameter of the object-endhole 416 is To, the following condition can be satisfied:1.35<TL/φo<2.75. Therefore, it is favorable for the plastic barrel 400applied to the optical lens assembly 1000 with high-end properties.Preferably, the following condition is satisfied: 1.50<TL/φo<2.25.

According to the 5th embodiment of the present disclosure, one of thestepped surfaces can form one of the annular grooves 440, when a numberof the annular grooves 440 is M, the following condition can besatisfied: 1≦M≦8. Therefore, it is favorable for maintaining the effectsof reducing the reflected lights of the stepped surfaces.

Furthermore, one of the stepped surfaces can form one of the annulargrooves or other structure. The stepped surfaces can be orthogonal tothe central axis, parallel to the central axis or neither of the above,such as sawtooth shape.

The data of the aforementioned parameters of the optical lens assembly1000 according to the 5th embodiment of the present disclosure arelisted in the following Table 5, wherein the number of the main ones ofthe annular grooves 440 of the plastic barrel 400 is M, and the data arealso shown as FIG. 4A and FIG. 4B.

TABLE 5 5th Embodiment φo (mm) 1.19 TL/φo 1.76 TL (mm) 2.10 M 3

6th Embodiment

FIG. 6 shows an electronic device 10 according to the 6th embodiment ofthe present disclosure. The electronic device 10 of the 6th embodimentis a smart phone, wherein the electronic device 10 includes an imagingapparatus 11, the imaging apparatus 11 includes an optical lens assembly(not shown) according to the present disclosure, and the optical lensassembly includes an plastic barrel (not shown) according to the presentdisclosure. Therefore, it is favorable for reducing the reflected lightseffectively and improving the image quality so as to satisfy therequirements of high-end electronic devices with camera functionalities.Furthermore, the imaging apparatus 11 can further include an imagesensor disposed on or near an image surface of the optical lensassembly. Preferably, the electronic device 10 can further include butnot limited to a display, a control unit, a storage unit, a randomaccess memory unit (RAM), a read-only memory unit (ROM) or a combinationthereof.

7th Embodiment

FIG. 7 shows an electronic device 20 according to the 7th embodiment ofthe present disclosure. The electronic device 20 of the 7th embodimentis a tablet personal computer, wherein the electronic device 20 includesan imaging apparatus 21, the imaging apparatus 21 includes an opticallens assembly (not shown) according to the present disclosure, and theoptical lens assembly includes an plastic barrel (not shown) accordingto the present disclosure.

8th Embodiment

FIG. 8 shows an electronic device 30 according to the 8th embodiment ofthe present disclosure. The electronic device 30 of the 8th embodimentis a head-mounted display, wherein the electronic device 30 includes animaging apparatus 31, the imaging apparatus 31 includes an optical lensassembly (not shown) according to the present disclosure, and theoptical lens assembly includes an plastic barrel (not shown) accordingto the present disclosure.

Although the present disclosure has been described in considerabledetail with reference to the embodiments thereof, other embodiments arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the embodiments contained herein.It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the presentdisclosure. In view of the foregoing, it is intended that the presentdisclosure cover modifications and variations of this disclosureprovided they fall within the scope of the following claims.

What is claimed is:
 1. A plastic barrel, comprising: an object-endportion comprising an object-end surface and an object-end hole, whereinthe object-end surface comprises a plurality of annular grooves, whichare disposed coaxially to a central axis, and each of the annulargrooves comprises a stepped surface; an image-end portion comprising animage-end opening; and a tube portion connecting the object-end portionand the image-end portion.
 2. The plastic barrel of claim 1, wherein theannular grooves and the plastic barrel are formed integrally.
 3. Theplastic barrel of claim 2, wherein the object-end surface furthercomprises: an outer object-end surface; and an inner object-end surfacedisposed opposite to the outer object-end surface, wherein the outerobject-end surface is closer to an object than the inner object-endsurface; wherein the annular grooves are disposed on the outerobject-end surface.
 4. The plastic barrel of claim 2, wherein thestepped surface of each of the annular grooves comprises a plurality oforthogonal stepped surfaces orthogonal to the central axis, a number ofthe orthogonal stepped surfaces of at least one of the annular groovesis N, and the following condition is satisfied:4≦N≦8.
 5. The plastic barrel of claim 2, wherein a number of the annulargrooves is M, and the following condition is satisfied:2≦M≦8.
 6. The plastic barrel of claim 2, wherein a diameter of theobject-end hole is φo, and the following condition is satisfied:φo<4.5 mm.
 7. The plastic barrel of claim 6, wherein the stepped surfaceof each of the annular grooves comprises a plurality of orthogonalstepped surfaces orthogonal to the central axis, a sum of the orthogonalstepped surfaces of each of the annular grooves is ΣN, and the followingcondition is satisfied:7≦ΣN.
 8. The plastic barrel of claim 3, wherein the outer object-endsurface comprises an outer flat surface orthogonal to the central axis.9. The plastic barrel of claim 3, wherein the stepped surface of each ofthe annular grooves comprises a plurality of orthogonal stepped surfacesorthogonal to the central axis, one of the orthogonal stepped surfacesis a groove bottom, each of another two of the orthogonal steppedsurfaces is a groove end, and the outer object-end surface comprises anouter flat surface orthogonal to the central axis; wherein a distanceparallel to the central axis between the groove bottom and the outerflat surface is greatest among distances parallel to the central axisbetween the orthogonal stepped surfaces and the outer flat surface, thetwo groove ends are disposed on two ends of the annular groovesrespectively, and a distance parallel to the central axis between eachof the two groove ends and the outer flat surface is smaller thandistances parallel to the central axis between the orthogonal steppedsurfaces adjacent to thereof and the outer flat surface; wherein thedistance parallel to the central axis between one of the two groove endsand the outer flat surface is smaller than the distance parallel to thecentral axis between the other one of the two groove ends and the outerflat surface, a distance parallel to the central axis between the one ofthe two groove ends and the groove bottom is h, and the followingcondition is satisfied:0.02 mm<h<0.25 mm.
 10. The plastic barrel of claim 9, wherein a sum ofthe orthogonal stepped surfaces of each of the annular grooves is ΣN,and the following condition is satisfied:7≦ΣN.
 11. The plastic barrel of claim 1, wherein a distance parallel tothe central axis between the object-end hole and the image-end openingis TL, a diameter of the object-end hole is φo, and the followingcondition is satisfied:1.35<TL/φo<2.75.
 12. The plastic barrel of claim 11, wherein thedistance parallel to the central axis between the object-end hole andthe image-end opening is TL, the diameter of the object-end hole is To,and the following condition is satisfied:1.50<TL/φo<2.25.
 13. The plastic barrel of claim 12, wherein the steppedsurface of each of the annular grooves comprises a plurality oforthogonal stepped surfaces orthogonal to the central axis, a sum of theorthogonal stepped surfaces of each of the annular grooves is ΣN, andthe following condition is satisfied:7≦ΣN.
 14. The plastic barrel of claim 1, wherein the tube portioncomprises a screw thread.
 15. An optical lens assembly, comprising: aplastic barrel, comprising: an object-end portion comprising anobject-end surface and an object-end hole, wherein the object-endsurface comprises a plurality of stepped surfaces disposed coaxially toa central axis; an image-end portion comprising an image-end opening;and a tube portion connecting the object-end portion and the image-endportion; and a lens module disposed in the plastic barrel and comprisinga plurality of lens elements; wherein a diameter of the object-end holeis φo, and the following condition is satisfied:φo<4.5 mm.
 16. The optical lens assembly of claim 15, wherein theplastic barrel is formed by an injection molding method.
 17. The opticallens assembly of claim 16, wherein the object-end hole is an aperturestop of the optical lens assembly.
 18. The optical lens assembly ofclaim 15, wherein a distance parallel to the central axis between theobject-end hole and the image-end opening is TL, a diameter of theobject-end hole is φo, and the following condition is satisfied:1.35<TL/φo<2.75.
 19. The optical lens assembly of claim 18, wherein thedistance parallel to the central axis between the object-end hole andthe image-end opening is TL, the diameter of the object-end hole is φo,and the following condition is satisfied:1.50<TL/φo<2.25.
 20. The optical lens assembly of claim 16, wherein atleast one of the stepped surfaces forms an annular groove, a number ofthe annular groove is M, and the following condition is satisfied:1≦M≦8.
 21. An imaging apparatus, comprising: the optical lens assemblyof claim
 15. 22. An electronic device, comprising: the imaging apparatusof claim 21.